diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5c2b4e0..0e64a3b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Added
 
 - Field `crmToken` for `Owner`
+- Field `externalInvoice` and `shortCode` for `Order`
 
 ## [1.0.0] - 2022-07-27
 
diff --git a/src/Order.hs b/src/Order.hs
index a8d01ef..758c48b 100644
--- a/src/Order.hs
+++ b/src/Order.hs
@@ -27,11 +27,13 @@ data ZGoOrder =
     , qtotalZec :: Double
     , qlines :: [LineItem]
     , qpaid :: Bool
+    , qexternalInvoice :: T.Text
+    , qshortCode :: T.Text
     }
   deriving (Eq, Show, Generic)
 
 instance ToJSON ZGoOrder where
-  toJSON (ZGoOrder i a s ts c cur p t tZ l paid) =
+  toJSON (ZGoOrder i a s ts c cur p t tZ l paid eI sC) =
     case i of
       Just oid ->
         object
@@ -46,6 +48,8 @@ instance ToJSON ZGoOrder where
           , "totalZec" .= tZ
           , "lines" .= l
           , "paid" .= paid
+          , "externalInvoice" .= eI
+          , "shortCode" .= sC
           ]
       Nothing ->
         object
@@ -60,6 +64,8 @@ instance ToJSON ZGoOrder where
           , "totalZec" .= tZ
           , "lines" .= l
           , "paid" .= paid
+          , "externalInvoice" .= eI
+          , "shortCode" .= sC
           ]
 
 instance FromJSON ZGoOrder where
@@ -76,6 +82,8 @@ instance FromJSON ZGoOrder where
       tZ <- obj .: "totalZec"
       l <- obj .: "lines"
       pd <- obj .: "paid"
+      eI <- obj .: "externalInvoice"
+      sC <- obj .: "shortCode"
       pure $
         ZGoOrder
           (if not (null i)
@@ -91,9 +99,11 @@ instance FromJSON ZGoOrder where
           tZ
           l
           pd
+          eI
+          sC
 
 instance Val ZGoOrder where
-  val (ZGoOrder i a s ts c cur p t tZ l pd) =
+  val (ZGoOrder i a s ts c cur p t tZ l pd eI sC) =
     if isJust i
       then Doc
              [ "_id" =: i
@@ -107,6 +117,8 @@ instance Val ZGoOrder where
              , "totalZec" =: tZ
              , "lines" =: l
              , "paid" =: pd
+             , "externalInvoice" =: eI
+             , "shortCode" =: sC
              ]
       else Doc
              [ "address" =: a
@@ -119,6 +131,8 @@ instance Val ZGoOrder where
              , "totalZec" =: tZ
              , "lines" =: l
              , "paid" =: pd
+             , "externalInvoice" =: eI
+             , "shortCode" =: sC
              ]
   cast' (Doc d) = do
     i <- B.lookup "_id" d
@@ -132,7 +146,9 @@ instance Val ZGoOrder where
     tZ <- B.lookup "totalZec" d
     l <- B.lookup "lines" d
     pd <- B.lookup "paid" d
-    Just (ZGoOrder i a s ts c cur p t tZ l pd)
+    eI <- B.lookup "externalInvoice" d
+    sC <- B.lookup "shortCode" d
+    Just (ZGoOrder i a s ts c cur p t tZ l pd eI sC)
   cast' _ = Nothing
 
 -- Type to represent an order line item
@@ -192,6 +208,8 @@ updateOrderTotals o =
        else 0)
     (qlines o)
     (qpaid o)
+    (qexternalInvoice o)
+    (qshortCode o)
   where
     newTotal :: ZGoOrder -> Double
     newTotal x = foldr tallyItems 0 (qlines x)
diff --git a/test/Spec.hs b/test/Spec.hs
index 83cd2b9..91751bf 100644
--- a/test/Spec.hs
+++ b/test/Spec.hs
@@ -249,6 +249,8 @@ main = do
                     0
                     []
                     False
+                    ""
+                    ""
             let ordTest = val myOrder
             case ordTest of
               Doc oT -> access p master "test" (insert_ "orders" oT)
@@ -538,6 +540,8 @@ startAPI config = do
           0
           []
           False
+          ""
+          ""
   let ordTest = val myOrder
   case ordTest of
     Doc oT -> access pipe master "test" (insert_ "orders" oT)
@@ -567,7 +571,9 @@ instance Arbitrary ZGoOrder where
     t <- arbitrary
     tZ <- arbitrary
     l <- arbitrary
-    ZGoOrder i a s ts c cur p t tZ l <$> arbitrary
+    pd <- arbitrary
+    eI <- arbitrary
+    ZGoOrder i a s ts c cur p t tZ l pd eI <$> arbitrary
 
 instance Arbitrary LineItem where
   arbitrary = do